1. Field of the Invention
This invention relates to novel metal detector assemblies and more particularly to a metal detector with a spring-loaded hinge-support and to an improved method of searching for metal objects hidden in the ground.
2. Brief Description of the Prior Art
Use of hand held metal detectors to search for metal objects hidden in the ground is well known. Most metal detectors of this type consist of a generally rectangular box having a handle on the top and a rigid shaft connected to the bottom of the box frame and extending outwardly therefrom. A disc or ring shaped head member is attached to other end of the shaft. The user holds the metal detector by the handle and swings the head in horizontal arcuate path over the ground as he walks about. As the detector passes over a metal object the user is alerted by an audible or a visual signal.
Often the search will take many hours resulting in fatigue of the arm of the user. Sometimes if the arcuate sweeping action of the detector head is too fast or irregular a false signal is given to the user. As a result, there is a considerable need for a means to interconnect the hand held box member and the head shaft member of metal detectors which will allow a smooth regular sweeping action with a minimum of effort on the part of the user.
Forbes, U.S. Pat. No. 1,982,910 discloses a mop or other utensil connected to the lower member of a two member handle handle having a pivot between the upper and lower members. The pivoting device uses a coiled helical spring which tends to draw the two members back into alignment from the pivoted position. A leaf spring is mounted within the helical spring so that the flexing action acts in one plane only. The construction permits a bend in the handle upon application of bending force so that a mop or brush may be used underneath low articles of furniture. The particular construction is not be suitable for use with metal detectors because it would not be operable by a slight wrist action of the user as is the present invention which may be easily installed on existing detectors by a slight modification of the shaft member.
Lauterbach, U.S. Pat. No. 2,191,348 discloses a two member pivoted handle for a dust mop, broom, or the like. The device uses a tension spring and alternatively a leaf spring to draw the two members into line and contains a means to normally restrain the two members from pivotal movement except on the application of an appreciable bending force on the handle. The Lauterbach device pivots in one direction only and thus is incapable of performing a smooth horizontal swinging action as required for use with metal detectors and found in the present invention.
The prior art in general, and none of these patents in particular, disclose a spring-loaded hinge-support for interconnecting the hand held box component and the head shaft component of metal detectors comprising a frame attachment member and a pivotally connected shaft attachment member.